Organoborane amine complex polymerization initiators and polymerizable compositions

ABSTRACT

The invention is a two part composition useful for initiating cure of one or more polymerizable monomers which cure when exposed to free radicals comprising in one part an organoboraneamine complex and in a second part an isocyanate which is capable of decomplexing the organoborane complex wherein the ratio of amine nitrogen atoms to boron atoms is greater than 4.0:1.0. In another embodiment the invention is a two part polymerizable composition comprising 
     part 1, a) an organoborane amine complex; and 
     part 2, b) one or more of monomers, oligomers or polymers having olefinic unsaturation which is capable of polymerization by free radical polymerization 
     c) an effective amount of a compound which causes the complex to disassociate thereby freeing the borane to initiate polymerization of the one or more monomers, oligomers or polymers having olefinic unsaturation wherein the compound which causes disassociation of the complex is kept separate from the complex until initiation of polymerization is desired; and 
     d) a material which manages the heat of the polymerization reaction such that adhesion to the substrate is maintained, which material can be located in either part 1, part 2 or both parts.

BACKGROUND OF THE INVENTION

This invention relates to compositions which contain organoborane aminecomplexes useful for initiating polymerization of compounds by freeradical means. In another embodiment, this invention relates topolymerizable compositions comprising compounds containing moietiescapable of free radical polymerization and organoborane amine complexinitiators of the invention. In yet another embodiment the inventionrelates to a method of polymerizing compounds containing moietiescapable of free radical polymerization.

In many practical situations in which compounds are subjected topolymerization or where adhesives are used, it is desirable to havepolymerizable compositions and adhesive compositions which can cure ondemand. Cure on demand means that the polymerization can be initiatedwhen desired. A significant problem with cure on demand compositions isthe stability of the compositions. Many such compositions will begincuring at, or near, ambient temperature or will partially cure atambient temperature resulting in an increased viscosity causingdifficulties in handling and reduced functionality of the polymerizablecomposition or adhesive composition.

Low surface energy olefins such as polyethylene, polypropylene andpolytetrafluroethylene have a variety of attractive properties in avariety of uses, such as for toys, automobile parts, furnitureapplications and the like. Because of the low surface energy of theseplastic materials, it is very difficult to find adhesive compositionswhich bond to these materials. The commercially available adhesiveswhich are used for these plastics require time consuming or extensivepretreatment of the surface before the adhesive will bond to thesurface. Such pretreatments include corona treatment, flame treatmentand the like. The requirement for extensive pretreatment of the surfaceresults in significant limitations to the designers of automobilecomponents, toys, furniture and the like. What are needed are adhesivecompositions which are capable of bonding to low surface energysubstrates, and bonding low surface energy substrates to othersubstrates, without the need for extensive or costly pretreatment.

Mottus et al., U.S. Pat. No. 3,275,611 (incorporated herein byreference) discloses a process for polymerizing olefinic compounds witha catalyst comprising an organoborane compound, a peroxygen compound andan amine. It is disclosed that the organoborane compound and amine maybe added to the reaction mixture separately or as a preformed complex,and that the complex is preferred. The presence of the amine in thecomplex reduces the pyrophoricity of the organoborane in air. Among theamine complexing agents disclosed are pyridine, aniline, toluidine,dimethylbenzylamine, and nicotine. Many of the complexes disclosed inMottus are pyrophoric at all amine to boron atom ratios. In addition,many of the amine complexes do not display significant adhesiveproperties when applied to low surface energy substrates.

A series of patents issued to Skoultchi (U.S. Pat. Nos. 5,106,928,5,143,884, 5,286,821, 5,310,835 and 5,376,746 (all incorporated hereinby reference)) disclose a two-part initiator system that is useful inacrylic adhesive compositions. The first part of the two-part systemincludes a stable organoborane amine complex and the second partincludes a destabilizer or activator such as an organic acid or analdehyde. The organoborane compound of the complex has three ligandswhich can be selected from C₁₋₁₀ alkyl groups or phenyl groups. Usefulamines disclosed include octylamine, 1,6-diaminohexane, diethylamine,dibutylamine, diethylenetriamine, dipropylenediamine, 1,3-propylenediamine, and 1,2-propylene diamine. The adhesive compositions aredisclosed to be useful in structural and semi-structural adhesiveapplications, such as speaker magnets, metal to metal bonding,automotive glass to metal bonding, glass to glass bonding, circuit boardcomponent bonding, bonding select plastics to metal, glass to wood, etc.and for electric motor magnets.

Zharov et al. discloses in a series of U.S. Patents (U.S. Pat. No.5,539,070; U.S. Pat. No. 5,690,780; and U.S. Pat. No. 5,691,065 (allincorporated herein by reference)) polymerizable acrylic compositionswhich are particularly useful as adhesives wherein organoborane aminecomplexes are used to initiate cure. The organoboranes used have threeligands attached to the borane atom which are selected from C₁₋₁₀ alkylgroups and phenyl. The amine is an alkanol amine, a linear alkyl diaminewhere the first amine group can be a primary or secondary amine and thesecond amine is a primary amine or an aromatic substituted alkyl amine.It is disclosed that these complexes are good for initiatingpolymerization of an adhesive which bonds to low surface energysubstrates.

Pocius in a series of patents (U.S. Pat. No. 5,616,796; U.S. Pat. No.5,621,143; U.S. Pat. No. 5,681,910; U.S. Pat. No. 5,686,544; U.S. Pat.No. 5,718,977; and U.S. Pat. No. 5,795,657 (all incorporated herein byreference) disclose amine organoborane complexes with a variety ofamines such as polyoxyalkylene polyamines and polyamines which are thereaction product of diprimary amines and compound having at least twogroups which react with a primary amine. Pocius U.S. Pat. No. 5,686,544discloses a composition comprising an organoborane polyamine complex,polyol and an isocyanate decomplexing agent. It is disclosed that theprimary amine to boron ratio in the complex is between about 4:1 and 1:1and most preferred at about 1:1.

Many of the complexes disclosed in the Zharov, Skoultchi and PociusPatents are not stable in compositions containing olefinic unsaturationat, or near, ambient temperatures and thus the complexes disassociateand induce polymerization at, or near, ambient temperature with time.This instability at, or near, ambient temperature can result inpolymerization before desired and can result in compositions which areunsuitable for the desired use. Further, the compositions generally aretwo part compositions in which one side is a resin side and the otherside is a hardener. One side (hardener) contains the organoboranecomplex and the other contains the decomplexing agent. In most cases thevolume ratio of the two parts is significantly different, that isgreater, than 4:1, often greater than 10:1. The problem is that mostcommercial equipment designed to dispense two part compositions utilizesratios of 4:1 or less. In order to get these compositions to work insuch equipment resin or nonreactive ingredients are added to one side orthe other to get a suitable volumetric ratio. The problem is that ifresin is added to the side containing the complex the mixture isunstable and could begin to cure at ambient temperatures and render thecomposition useless. If excessive inert materials are added to thehardener side the inert ingredient can act as a plasticizer or create aweak continuous phase and negatively impact the properties of thepolymerized composition.

After polymerization many of the compositions of the prior artdemonstrate excellent stability, strength and adhesion at or nearambient temperatures, but at elevated temperatures undergo loss ofstrength and adhesion at significantly elevated temperatures. Thislimits the environments where substrates bonded using these adhesivescan be used.

Therefore, there is a need for initiator systems for free radicalpolymerization which are safe to handle, not pyrophoric, which can beused to form cure on demand polymer systems or can be used in adhesivesystems which cure on demand. What is further needed are adhesivesystems which are capable of bonding to low surface energy substrates,and initiator systems which facilitate such bonding. In addition to suchneeds, the complexes need to be thermally stable, that is do notdisassociate at, or near, ambient temperatures and thereby initiatepolymerization before desired. What are further needed are polymercompositions and adhesive systems which are thermally stable at, ornear, ambient temperatures and which will undergo polymerization whenthe user desires. Further compositions that can be used in existingcommercial equipment at mix ratios of 4:1 or less are needed.Compositions that have stability, strength and adhesion at elevatedtemperatures are desired.

SUMMARY OF INVENTION

The invention is a two part composition useful for initiating cure ofone or more polymerizable monomers which cure when exposed to freeradicals comprising in one part an organoborane amine complex and in asecond part an isocyanate which is capable of decomplexing theorganoborane complex wherein the ratio of amine nitrogen atoms to boronatoms is greater than 4.0:1.0.

In another embodiment the invention is a two part polymerizablecomposition comprising

part 1, a) an organoborane amine complex wherein the ratio of aminenitrogen atoms to boron atoms is greater than 4.0:1; and

part 2, b) one or more of monomers, oligomers or polymers havingolefinic unsaturation which is capable of polymerization by free radicalpolymerization. In a preferred embodiment the second part (part 2)further comprises an effective amount of an isocyanate which causes thecomplex of part 1 to disassociate, freeing the borane to initiatepolymerization of the one or more monomers, oligomers or polymers havingolefinic unsaturation. In this embodiment the decomplexing agent and thecomplex are kept in separate parts to prevent premature reaction.

The invention is also a method of polymerization comprising contactingthe components of the polymerizable composition under conditions suchthat the one or more monomers, oligomers, or polymers undergopolymerization. In one embodiment, the contacting occurs at, or near,ambient temperature. In another embodiment, the method further comprisesthe step of heating the polymerized composition to an elevatedtemperature under conditions such that the amine and isocyanate mayfurther react. This can improve the temperature resistance of thepolymerized composition.

In yet another embodiment the invention is a method of bonding two ormore substrates together which comprises contacting the components ofthe polymerizable composition together under conditions such thatpolymerization is initiated; contacting the polymerizable compositionwith the two or more substrates; positioning the two or more substratessuch that the polymerizable composition is located between the two ormore substrates; and allowing the polymerizable composition topolymerize and to bond the two or more substrates together.

In yet another embodiment the invention is a method of coating asubstrate composition which comprises contacting a compositioncomprising

a) an organoborane amine complex wherein the ratio of amine nitrogenatoms to boron atoms is greater than 4.0:1 and

b) one or more monomers, oligomers or polymers having olefinicunsaturation which are capable of polymerization by free radicalpolymerization

with one or more surfaces of a substrate and heating the coating toinitiate cure of the coating.

In another embodiment the invention is a method of coating a substratewherein the coating composition comprises

a) an organoborane amine complex wherein the ratio of amine nitrogenatoms to boron atoms is greater than 4.0:1 and

b) one or more monomers, oligomers or polymers having olefinicunsaturation which are capable of polymerization by free radicalpolymerization; and

c) a decomplexing agent.

In another embodiment the invention is a laminate comprising twosubstrates having disposed between the substrates and bound to eachsubstrate a composition comprising

a) an organoborane amine complex wherein the ratio of amine nitrogenatoms to boron atoms is greater than 4.0:1 and

b) one or more monomers, oligomers or polymers having olefinicunsaturation which are capable of polymerization by free radicalpolymerization.

The composition in such laminate may further comprise a decomplexingagent.

In yet another embodiment the invention is a two part polymerizablecomposition comprising

part 1, a) an organoborane amine complex; and

part 2, b) one or more of monomers, oligomers or polymers havingolefinic unsaturation which is capable of polymerization by free radicalpolymerization

c) an effective amount of a compound which causes the complex todisassociate thereby freeing the borane to initiate polymerization ofthe one or more monomers, oligomers or polymers having olefinicunsaturation wherein the compound which causes disassociation of thecomplex is kept separate from the complex until initiation ofpolymerization is desired; and

d) a material which manages the heat of the polymerization reaction suchthat adhesion to the substrate is maintained, which material can belocated in either part 1, part 2 or both parts.

The complexes of the invention are safe to handle, i.e., not pyrophoric,are stable at, or near, ambient temperature and therefore will notinitiate polymerization at, or near, ambient temperature in the absenceof an initiator that causes the complex to disassociate. The polymericcompositions of the invention are stable at, or near, ambienttemperature and can be cured upon demand by contacting the complex withthe compounds which cause disassociation of the complex, oralternatively by heating the polymeric compositions above the thermaldisassociation temperature of the complex. Furthermore, thepolymerizable compositions of the invention can form good bonds to lowsurface energy substrates without the need for primers or surfacetreatment. These polymerizable compositions can be used as adhesives,coatings and can be used to laminate substrates together. The complexesand polymerizable compositions of the invention may be formulated to bedispensed in commercial equipment at volume ratios of the two parts of4:1 or less. The polymerized compositions demonstrate excellent cohesiveand adhesive strength at elevated temperatures and thus demonstrateexcellent stability at high temperatures.

DESCRIPTION OF FIGURES

FIG. 1 illustrates the lap shear strengths of adhesives as a function ofamine to boron atom ratio.

FIG. 2 illustrates the cure rate of adhesives at various amine nitrogento boron atomic ratios.

DETAILED DESCRIPTION OF THE INVENTION

The organoborane used in the complex is a trialkyl borane or an alkylcycloalkyl borane. Preferably such borane corresponds to Formula 1:

BR²)₃  Formula 1

wherein B represents Boron; and R² is separately in each occurrence aC₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl, or two or more of R² may combine to forma cycloaliphatic ring. Preferably R² is C₁₋₄ alkyl, even more preferablyC₂₋₄ alkyl, and most preferably C₃₋₄ alkyl. Among preferredorganoboranes are tri-ethyl borane, tri-isopropyl borane andtri-n-butylborane.

To prepare thermally stable polymerizable compositions, thermally stablecomplexes which do not disassociate, at or near, ambient temperature areneeded. The key to preparation of such complexes, is the selection ofthe amine. The desirability of the use of a given amine in anorganoborane amine complex can be calculated from the energy differencebetween the Lewis acid-base complex and the sum of energies of theisolated Lewis acid (organoborane) and base (amine) known as bindingenergy. The higher (more negative) the binding energy the more stablethe complex.

Binding Energy=−(Complex Energy−(Energy of Lewis Acid+Energy of Lewisbase))

Such binding energies can be calculated using theoretical ab initiomethods such as the Hartree Fock method and the 3-21G basis set. Thesecomputational methods are available commercially employing commercialsoftware and hardware such as SPARTAN and GAUSSIAN 98 programs with aSilicon Graphics workstation. Amines having amineorganoborane bindingenergies of ten kilocalories per mol or greater are preferred, amineshaving a binding energy of 15 kilocalories per mol or greater are morepreferred and even more preferred are amines with a binding 20kilocalories per mol or greater. In the embodiment where polymerizationof the compositions of the invention is initiated by use of adecomplexing agent the binding energy of the amine to the organoboraneis preferably about 50 kcal/mole or less and most preferably about 30kcal/mole or less. In the embodiment where polymerization of thecompositions of the invention is initiated by use of heat the bindingenergy of the amine is preferably about 100 kcal/mole or less, morepreferably about 80 kcal/mole or less and most preferably about 50kcal/mole or less.

The amines used to complex the organoborane compound can be any aminesor mixture of amines which complex the organoborane and which can bedecomplexed when exposed to a decomplexing agent. Preferred aminesinclude the primary or secondary amines or polyamines containing primaryor secondary amine groups, or ammonia as disclosed in Zharov U.S. Pat.No. 5,539,070 at column 5 lines 41 to 53, incorporated herein byreference, Skoultchi U.S. Pat. No. 5,106,928 at column 2 line 29 to 58incorporated herein by reference, and Pocius U.S. Pat. No. 5,686,544column 7, line 29 to Column 10 line 36 incorporated herein by reference;ethanolamine, secondary dialkyl diamines or polyoxyalkylenepolyamines;and amine terminated reaction products of diamines and compounds havingtwo or more groups reactive with amines as disclosed in Deviny U.S. Pat.No. 5,883,208 at column 7 line 30 to column 8 line 56, incorporatedherein by reference. With respect to the reaction products described inDeviny the preferred diprimary amines include alkyl diprimary amines,aryl diprimary amines, alkyaryl diprimary amines and polyoxyalkylenediamines; and compounds reactive with amines include compounds whichcontain two or more groups of carboxylic acids, carboxylic acid esters,carboxylic acid halides, aldehydes, epoxides, alcohols and acrylategroups. Preferred amines include n-octylamine, 1,6-diaminohexane(1,6-hexane diamine), diethylamine, dibutyl amine, diethylene triamine,dipropylene diamine, 1,3-propylene diamine (1,3-propane diamine),1,2-propylene diamine, 1,2-ethane diamine, 1,5-pentane diamine,1,12-dodecanediamine, 2-methyl-1,5-pentane diamine, 3-methyl-1,5-pentanediamine, triethylene tetraamine, diethylene triamine. Preferredpolyoxyalkylene polyamines include polyethyleneoxide diamines,polypropyleneoxide diamines, triethylene glycol propylene diamine,polytetramethyleneoxide diamine andpolyethyleneoxidecopolypropyleneoxide diamines.

In one preferred embodiment, the amine comprises a compound having aprimary amine and one or more hydrogen bond accepting groups, whereinthere are at least two carbon atoms, preferably at least about three,between the primary amine and hydrogen bond accepting groups.Preferably, an alkylene moiety is located between the primary amine andthe hydrogen accepting group. Hydrogen bond accepting group means hereina functional group that through either inter- or intramolecularinteraction with a hydrogen of the borane-complexing amine increases theelectron density of the nitrogen of the amine group complexing with theborane. Preferred hydrogen bond accepting groups include primary amines,secondary amines, tertiary amines, ethers, halogen, polyethers,thioethers and polyamines. In a preferred embodiment, the aminecorresponds to Formula 2:

wherein:

R¹ is separately in each occurrence hydrogen, a C₁₋₁₀ alkyl, C₃₋₁₀cycloalkyl or two or more of R¹ can form a cyclic ring structure whichmay have one or more cyclic rings; X is hydrogen bond accepting moiety;a is an integer of about 1 to about 10; and b is separately in eachoccurrence an integer of about 0 to about 1, and the sum of a and b isfrom about 2 to about 10. Preferably R¹ is hydrogen, methyl or two ormore of R¹ combine to form a 5 or 6 membered cyclic ring. In a preferredembodiment X is a hydrogen accepting moiety with the proviso that whenthe hydrogen accepting moiety is an amine it is a tertiary or asecondary amine. More preferably X is separately in each occurrence—N(R⁸)_(e), —OR¹⁰, —SR¹⁰ or a halogen. R⁸ is separately in eachoccurrence C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl, —(C(R¹)₂)_(d)—W or two of R⁸may combine to form a structure having one or more cyclic rings. R¹⁰ isseparately in each occurrence, C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl, or—(C(R¹)₂)_(d)—W. E is separately in each occurrence 0, 1, or 2; and mostpreferably e is 2. More preferably X is —N(R⁸)₂ or —OR¹⁰. Preferably, R⁸and R¹⁰ are C₁₋₄ alkyl or —(C(R¹)₂)_(d)—W, more preferably C₁₋₄ alkyland most preferably methyl. W is separately in each occurrence hydrogenor C₁₋₁₀ alkyl or X and more preferably hydrogen or C₁₋₄ alkyl.Preferably, a is about 1 or greater and more preferably about 2 orgreater. Preferably a is about 6 or less, and most preferably about 4 orless. Preferably, b is about 1. Preferably, the sum of a and b is aninteger about 2 or greater and most preferably about 3 or greater.Preferably the sum of a and b are about 6 or less and more preferablyabout 4 or less. Preferably d is separately in each occurrence aninteger of about 1 to about 4, more preferably about 2 to about 4, andmost preferably about 2 to about 3. Among preferred amines correspondingto Formula 2 are dimethylaminopropyl amine, methoxypropyl amine,dimethylaminoethylamine, dimethylaminobutylamine, methoxybutyl amine,methoxyethyl amine, ethoxypropylamine, propoxypropylamine, amineterminated polyalkylene ethers (such as trimethylolpropanetris(poly(propyleneglycol), amine terminated)ether), andaminopropylpropanediamine.

In one embodiment the preferred amine complex corresponds to Formula 3:

wherein R¹, R², X, a and b are as defined hereinbefore.

In another embodiment the amine is an aliphatic heterocycle having atleast one nitrogen in the heterocycle. The heterocyclic compound mayalso contain one or more of nitrogen, oxygen, sulfur or double bonds. Inaddition, the heterocycle may comprise multiple rings wherein at leastone of the rings has a nitrogen in the ring. Preferably the aliphaticheterocyclic amine corresponds to Formula 4:

wherein:

R³ is separately in each occurrence hydrogen, a C₁₋₁₀ alkyl C₃₋₁₀cycloalkyl or forms a double bond with an adjacent atom. R^(4′) isseparately in each occurrence hydrogen, C₁₋₁₀ alkyl or forms a cyclicring with an R³, Z or a substituent on Z. Z is separately in eachoccurrence sulfur, oxygen or —NR⁴. R⁴ is separately in each occurrencehydrogen, C₁₋₁₀ alkyl, or C₆₋₁₀ aryl or C₇₋₁₀ alkaryl. X is separatelyin each occurrence an integer of about 1 to about 10, with the provisothat the total of all occurrences of x should be from about 2 to about10. Y is separately in each occurrence 0 or 1. Two or more of R³, R⁴,and R^(4′) may combine to form cyclic rings thereby forming amulticyclic compound. Preferably, R³ is separately in each occurrencehydrogen, methyl or forms a double bond with an adjacent atom.Preferably Z is NR⁴. Preferably, R⁴ is hydrogen or C₁₋₄ alkyl, and morepreferably hydrogen or methyl. Preferably, R^(4′) is hydrogen or C₁₋₄alkyl, more preferably hydrogen or methyl and most preferably hydrogen.Preferably x is from about 1 to about 5 and the total of all theoccurrences of x is about 3 to about 5. Preferred compoundscorresponding to Formula 4 include morpholine, piperidine, pyrolidine,piperazine, 1,3,3 trimethyl 6-azabicyclo[3,2,1] octane, thiazolidine,homopiperazine, aziridine, 1-amino-4-methylpiperazine, 3-pyrroline,aminopropyl morpholine and the like. Complexes containing aliphaticheterocyclic amines preferably correspond to Formula 5:

wherein R², R³, R^(4′), Z, x and y are as defined hereinbefore.

In yet another embodiment, the amine which is complexed with theorganoborane is an amidine. Any compound with amidine structure whereinthe amidine has sufficient binding energy as described hereinbefore withthe organoborane, may be used. Preferable amidine compounds correspondto Formula 6:

wherein:

R⁵ separately in each occurrence hydrogen, a C₁₋₁₀ alkyl, or C₃₋₁₀cycloalkyl. R⁶ is separately in each occurrence hydrogen, a C₁₋₁₀ alkyl,C₃₋₁₀ cycloalkyl or N(R⁵)₂. Two or more of R⁵, R⁶, and R⁷ may combine inany combination to form a ring structure, which may have one or morerings. Preferably R⁵ is separately in each occurrence hydrogen, C₁₋₄alkyl or C₅₋₆ cycloalkyl. Preferably R⁶ is separately in each occurrencehydrogen, C₁₋₄ alkyl or C₅₋₆ cycloalkyl or N(R⁵)₂. More preferably R⁶ isseparately in each occurrence C₁₋₄ alkyl or C₅₋₆ cycloalkyl or N(R⁵)₂Preferably R⁷ is separately in each occurrence hydrogen, C₁₋₁₀ alkyl,C₃₋₁₀ cycloalkyl or part of a ring structure. Most preferably R⁷ ishydrogen, methyl or part of a cyclic ring. In the embodiment where twoor more of R⁵, R⁶ and R⁷ combine to form a ring structure, the ringstructure is preferably a single or a double ring structure. Amongpreferred amidines are 1,1,3,3-tetramethylguanidine, 1,8diazobicyclo[5,4]undec-7ene; tetrahydropyrimidine;2-methyl-2-imidazoline and the like.

The organoborane amidine complexes preferably correspond to Formula 7:

wherein R², R⁵, R⁶ and R⁷ are as defined earlier.

In yet another embodiment, the amine which is complexed with theorganoborane is a conjugated imine. Any compound with a conjugated iminestructure, wherein the imine has sufficient binding energy as describedhereinbefore with the organoborane, may be used. The conjugated iminecan be a straight or branched chain imine or a cyclic imine. Preferableimine compounds correspond to Formula 8:

wherein Y is independently in each occurrence hydrogen, N(R⁴)₂, OR⁴,C(O)OR⁴, halogen, an alkylene group which forms a cyclic ring with R⁷ orR⁹. R⁹ is independently in each occurrence hydrogen, Y, C₁₋₁₀ alkyl,C₃₋₁₀ cycloalkyl-, (C(R⁹)₂—(CR⁹═CR⁹)_(c)—Y or two or more of R⁹ cancombine to form a ring structure provided the electron rich group in Yis conjugated with respect to the double bond of the imine nitrogen; andc is an integer of from about 1 to about 10. Preferably, R⁹ is hydrogenor methyl.

Y is preferably N(R⁴)₂, SR⁴, OR⁴, or an alkylene group which forms acyclic ring with R⁹. Y is more preferably N(R⁴)₂ or an alkylene groupwhich forms a cyclic ring with R⁹. Preferably, c is an integer of fromabout 1 to about 5, and most preferably about 1. Among preferredconjugated imines useful in this invention are 4-dimethylaminopyridine;2,3-bis(dimethylamino)cyclopropeneimine; 3-(dimethylamino)acroleinimine;3-(dimethylamino)methacroleinimine, and the like.

Among preferred cyclic imines are those corresponding to the followingstructures

The complexes with the conjugated imines preferably correspond toFormula 9:

wherein R², R⁷, R⁹, c and Y are as defined hereinbefore.

In another embodiment the amine can be an alicyclic compound havingbound to the alicyclic ring a substituent containing an amine moiety.The amine containing alicyclic compound may have a second substituentwhich contains one or more nitrogen, oxygen, sulfur atoms or a doublebond. The alicyclic ring can contain one or two double bonds. Thealicyclic compound may be a single or multiple ring structure.Preferably the amine on the first substituent is primary or secondary.Preferably the alicyclic ring is a 5 or 6 membered ring. Preferablyfunctional groups on the second substituent are amines, ethers,thioethers or halogens. In a preferred embodiment the alicyclic compoundwith one or more amines containing substituent corresponds to Formula 10

wherein R³, X, b and x are as described hereinbefore. Included in aminesubstituted alicyclic compounds is isophorone diamine and isomers ofbis(aminoethyl cyclohexane.

Complexes using amine substituted alicyclic compounds correspond toFormula 11

wherein R², R³, X, b and x are as defined hereinbefore.

The equivalent ratio of amine compound(s) to borane compound in thecomplex is relatively important. An excess of amine is preferred toallow balancing of the volume of the resin side and the hardener side ofthe polymerizable compositions described herein. Further increasing theamine content further stabilizes the organoborane amine complex. Alsothe amine reacts with the decomplexing agent to produce a thermallystable urea polyurea or polyurea/urethane. Preferably the equivalentratio of amine compound to organoborane compound is about 4.0:1.0 orgreater. More preferably the equivalents ratio of amine compound toorganoborane compound is greater than about 4.0:1.0, even morepreferably about 5.0:1.0 or greater and most preferably about 6.0:1 orgreater. The upper limit on the amount of amine is based onpracticality, the amount of heat generated by the reaction of the amineand the isocyanate decomplexing agent, and on the amount of thedecomplexing agent present as discussed hereinafter. More preferably theequivalent ratio of amine compound to organoborane compound is about20.0:1.0 or less and most preferably about 16.0:1.0 or less.

Polymerizable compounds which may be used in the polymerizationcompositions of the invention include any monomers, oligomers, polymersor mixtures thereof which contain olefinic unsaturation which canpolymerize by free radical polymerization. Such compounds are well knownto those skilled in the art. Mottus, U.S. Pat. No. 3,275,611, provides adescription of such compounds at column 2, line 46 to column 4, line 16,incorporated herein by reference. Among preferred classes of compoundscontaining olefinic unsaturation are monomers, oligomers, polymers andmixtures thereof derived from the acrylates and methacrylates;olefinically unsaturated hydrocarbons, for example ethylene, propylene,butylene, isobutylene, 1-octene, 1-dodecene, 1-heptadecene, 1-eicoseneand the like; vinyl compounds such as styrene, vinyl pyridine,5-methyl-2-vinylpyridine, vinyl napthylene, alpha methylstyrene; vinyland vinylidiene halides; acrylonitrile and methacrylonitrile; vinylacetate and vinyl propionate; vinyl oxyethanol; vinyl trimethylacetate;vinyl hexonate; vinyl laurate; vinyl chloroacetate; vinyl stearate;methyl vinyl ketone; vinyl isobutyl ether; vinyl ethyl ether; compoundsthat have a plurality of ethylenic bonds such as those having conjugateddouble bonds such as butadiene, 2-chlorobutadiene, isoprene; and thelike. Examples of preferable acrylates and methacrylates are disclosedin Skoultchi, U.S. Pat. No. 5,286,821 at column 3, lines 50 to column 6,line 12, incorporated herein by reference and Pocius, U.S. Pat. No.5,681,910 at column 9, line 28 to column 12, line 25, incorporatedherein by reference. More preferred olefinic compounds comprise methylacrylate, methylmethacrylate, butylmethacrylate, tert-butylmethacrylate,2-ethylhexyacrylate, 2-ethylhexylmethacrylate, ethylacrylate,isobornylmethacrylate, isobornylacrylate, hydroxyethylmethacrylate,glycidylmethacrylate, tetrahydrofurfuryl methacrylate, acrylamide,n-methylacrylamide, and other similar acrylate containing monomers. Alsouseful are the class of acrylate tipped polyurethane prepolymersavailable commercially from several sources, and prepared by reacting anisocyanate reactive acrylate monomer, oligomer or polymer, such as ahydroxy acrylate, with an isocyanate functional prepolymer.

In the embodiment where the composition is used as an adhesive, acrylateand/or methacrylate based compounds are preferably used. The mostpreferred acrylate and methacrylate compounds includemethylmethacrylate, butylmethacrylate, 2-ethylhexylmethacrylate,isobornylmethacrylate, tetrahydrofurfuryl methacrylate, andcyclohexylmethylmethacrylate.

Preferably the polymerized composition of the invention is capable offorming a polymer that exhibits high temperature resistance. Hightemperature resistance means the polymer does not appreciably soften orundergo degradation at elevated temperatures. Preferably the polymer iscapable of withstanding temperatures of 10° C. in excess of theirexpected maximum use temperature. Preferably such use temperature isabout 60° C. or greater and more preferably about 90° C. or greater.Preferred monomers which prepare polymers with high temperatureresistance are methyl methacrylate (MMA), and isobornyl methacrylate.Preferred high temperature polymers are sPMMA (syndiotacticpolymethylmethacrylate), PMMA (polymethylmethacrylate), polyisobornylmethacrylate, polyacrylamide and crosslinked (meth)acrylic polymers.

The compositions of the invention further comprises an effective amountof an isocyanate containing compound (a decomplexing agent) that isreactive with the complexed amine so as to liberate the organoborane andto initiate polymerization. The amine reactive compound liberatesorganoborane by reacting with the amine, thereby removing theorganoborane from chemical attachment with the amine. Desirabledecomplexing agents are those isocyanates which can readily formreaction products with amines at, or below, and more preferably at roomtemperature, i.e., about 20° C. to 22° C., so as to provide acomposition that can be easily used and cured under ambient conditions.Preferably the amount of isocyanate containing compound present issufficient to cause the organoborane amine complexes present in thecomposition to decomplex. Preferably there is sufficient isocyanatecontaining compound present to react with all of the amine present.Excess amine can plasticize the polymer formed and thus compromise theproperties of the polymers formed. Preferably an excess of isocyanate ispresent as compared to the free total amount of active hydrogens(typically, primary and secondary amine and hydroxy groups) in theorganoborane amine complex. Preferably the ratio of isocyanateequivalents to amine equivalents is about 1.0:1.0 or greater, morepreferably about 1.1:1.0 or greater and most preferably about 1.25:1 orgreater as used here, this refers to any free amine and to complexedamine present. The isocyanate containing compounds react with the aminepresent in the composition to form a urea, polyurea or polyurethane/ureaphase. When an excess of isocyanate containing compound is used, littleor no free amine is present in the resulting product. By eliminating thepresence of free amine the plasticizing impact of the amine isprevented. Further the urea or polyurea present improves the heatresistance of the resulting product. Preferably the amount of urea orpolyurea present in the resulting polymerized product is about 5 percentby weight or greater, more preferably about 10 percent or greater, andmost preferably about 15 percent or greater. Preferably the amount ofpolyurea present in the resulting polymerized product is about 50percent or less, more preferably about 45 percent or less and mostpreferably about 40 percent or less. Percent urea means the percent byweight of the urea/urethane phase in the final product. This can begenerally determined by adding the weight of the isocyanate and amine(and any other isocyanate reactive compounds present) and dividing thissum by the total weight of the ingredients.

In one embodiment the polymer or adhesive formulation of the inventionmay further contain one or more compounds which have more than one,preferably two or more, moieties reactive with isocyanates. Generally,in addition to amines, moieties which contain active hydrogen atoms arereactive with isocyanate groups, such moieties include hydroxyl,carboxylate, and thiol moieties. After amines, the more preferred activehydrogen moieties are hydroxyl moieties. The preferred hydroxylcontaining compounds are polyols and aminols. Any polyol useful forreacting with isocyanates may be used. Preferably, primary and secondaryamines are the only compounds that are present to react with theisocyanate containing compounds. Preferably the isocyanate containingcompound is any isocyanate compound that decomplexes the organoboraneamine complex. Preferably the isocyanate is a polyisocyanate havingnominally 2 or greater isocyanate moieties per compound. Isocyanatecompounds useful are disclosed in Deviny U.S. Pat. No. 5,872,197, Column4 line 57 to column 5 line 65, incorporated herein by reference. Amongmore preferred isocyanate containing compounds are polymeric versions ofmethylene diphenyl diisocyanate, isophorone diisocyanate, hexamethylenediisocyanate, toluene diisocyanate, isomers or bis isocyanatomethylcyclohexane, tetramethylxylyl diisocyanate, and the like.

Preferably the amount of polymerizable compounds in the polymerizablecompositions or adhesive is about 20 percent by weight or greater basedon the weight of the total composition, more preferably about 30 percentby weight or greater and most preferably about 40 percent by weight orgreater. Preferably the amount of polymerizable compounds is about 95percent by weight or less, preferably about 90 percent by weight or lessand most preferably about 85 percent by weight or less. The amount ofcomplex used in the composition can be any amount sufficient to initiatepolymerization once the complex has disassociated. At higherconcentration of organoborane, the speed of polymerization is generallyhigher. Preferably the amount of organoborane complex present issufficient to provide the amount of boron of about 0.02 percent byweight or greater based on the weight of the total composition and morepreferably about 0.05 percent by weight or greater. Preferably theamount of organoborane complex present is sufficient to provide theamount of boron of about 1 percent by weight or less based on the totalweight of composition, preferably about 0.7 percent by weight or lessand most preferably about 0.4 percent by weight or less.

Preferably the amount of isocyanate present is about 80 equivalentspercent or greater based on the equivalents of amine present, bothcomplexed and free, more preferably about 100 equivalents percent orgreater and most preferably about 110 equivalents percent or greater.

Preferably the equivalent ratio of amine to isocyanate is 1.25:1.0 orless and more preferably is about 1.0:1.0 or less.

The organoborane amine complex may be readily prepared using knowntechniques. Typically, the amine is combined with the organoborane in aninert atmosphere with stirring. An exotherm is often observed andcooling of the mixture is, therefore, recommended. If the ingredientshave a high vapor pressure, it is desirable to keep the reactiontemperature below about 70° C. to 80° C. Once the materials are wellmixed the complex is permitted to cool to room temperature. The solventis then removed. No special storage conditions are required although itis preferred that the complex be kept in a capped vessel under an inertatmosphere, in a cool, dark location. Advantageously, the complexes ofthe invention can be prepared in the absence of organic solvents thatwould later have to be removed, although they could be prepared insolvent, if so desired. Solvents used in the preparation of thecomplexes should, preferably, be ones that do not coordinate the amine,preferable solvents are, for example, tetrahydrofuran or diethylether,or low molecular weight alkanes such as hexane or heptane.

The complexes useful in the invention are air stable. By “air stable” itis meant that when the complexes are stored in a capped vessel at roomtemperature (about 20° C. to 22° C.) and under otherwise ambientconditions (i.e., not under a vacuum and not in an inert atmosphere),the complexes remain useful as polymerization initiators for at leastabout two weeks, although the complexes may be readily stored underthese conditions for many months.

By “air stable” it is also meant that the complexes are not pyrophoric.(When a few drops of the complex are placed on a paper towel underambient conditions, the paper towel does not ignite, char or smoke.) Theair stability of the complex is enhanced when the complex is acrystalline material. However, the complexes of the invention are airstable for at least six months even when they are liquids. Liquidcomplexes are easier to handle and mix than are crystalline complexes.

The polymerizable compositions of the invention are two-partcompositions. In one embodiment the compositions are two-partcompositions in which one-part contains the complexes of the inventionand the other part contains the decomplexing agent (initiator).Polymerization is initiated by contacting the two-parts of thecomposition. Polymerization can be initiated at, or even below, ambienttemperatures. Heat may be applied to the polymerizable composition tospeed up initiation or polymerization and to aid in the reaction of theisocyanate compound present with the active hydrogen containingcompounds. The primary reason to use a two-part composition is to keepapart components of the composition which may be unstable in thepresence of one another.

In the embodiment where heat is used to effect the cure of thecomposition, the composition is exposed to a heat source which heats thecomposition to a temperature at or above the temperature at which thecomplex used in the composition decomposes to release the organoboranewhich then initiates free radical polymerization. Generally thecomposition is heated to a temperature which is less than thetemperature at which the monomer undergoes spontaneous polymerization.The temperature at which the complex undergoes disassociation is relatedto the binding energy of the complex. At higher binding energies of thecomplex higher temperatures are required to initiate polymerization.

Where the binding energy of the complex is high, polymerization may beinitiated thermally. The temperature at which the composition is heatedto initiate polymerization is dictated by the binding energy of thecomplex. Generally the temperature used to initiate the polymerizationby decomplexing the complex is about 30° C. or greater and preferablyabout 50° C. or greater. Preferably the temperature at which thermallyinitiated polymerization is initiated is about 120° C. or less and morepreferably about 100° C. or less. Any heat source which heats thecomposition to the desired temperature can be used, provided the heatsource does not negatively impact the components of the composition orits function. In this manner the composition may be contacted with thesubstrates either before or after the composition is exposed to heat. Ifthe composition is heated prior to contact with the substrates, thecomposition should be contacted with the substrates before thecomposition has polymerized to the point at which the composition is nolonger able to adhere to the substrates. It may be necessary in thethermally initiated reaction to control the oxygen content such thatthere is adequate oxygen to create favorable conditions for radicalformation but not so much as to inhibit the polymerization.

If heat is used (in addition to an initiator) to enhance cure, theapplied heat can be applied immediately or delayed (that is appliedafter some time of cure at room temperature). If a delayed heating orpost-cure heating is used, the polymerized composition may be exposed totemperatures as high as, or slightly higher than, the expected maximumuse temperature. Preferably, any delayed heating is applied aftersufficient strength has been achieved in the cured compound at roomtemperature. If heat is applied immediately to the curing compound toaccelerate the cure, then this heat is preferably less than orapproximately equal to the dissociation temperature of the organoboraneamine complex.

The two-part polymerizable compositions or adhesive compositions of theinvention are uniquely suited for use with conventional, commerciallyavailable dispensing equipment for two-part adhesives. Once thetwo-parts have been combined, the composition should be used quickly, asthe useful pot life (open time) may be short depending upon the monomermix, the amount of complex, and the temperature at which the bonding isto be performed. The adhesive composition is applied to one or bothsubstrates and then the substrates are joined together, preferably withpressure to force excess composition out of the bond line. In general,the bonds should be made shortly after the composition has been applied,preferably within about 10 minutes. The typical bond line thickness isabout 0.005 inches (0.13 mm) to about 0.03 inches (0.76 mm). The bondline can be thicker if gap filling is needed as the composition of theinvention can function as both an adhesive and a gap filler. The bondingprocess can easily be carried out at room temperature and to improve thedegree of bonding it is desirable to keep the temperature below about40° C., preferably below about 30° C., and most preferably below about25° C.

The bonds will cure to a reasonable green strength to permit handling ofthe bonded components within about 0.5 to 3 hours. Full strength will bereached in about 24 hours under ambient conditions. Post-curing withheat may be used if desired. After polymerization of the olefiniccompound has been initiated, the composition of the invention may beexposed to conditions to cause the polyisocyanate to react additionallywith the isocyanate reactive compound. Preferably this reaction isinitiated by exposing the composition to temperatures at which thepolyisocyanate reacts with the isocyanate reactive compounds. In anotherembodiment the composition may contain a catalyst for the reaction of anisocyanate with an isocyanate reactive compound. Such catalysts are wellknown in the art. Temperatures for post curing are preferably about 25°C. or greater and more preferably about 30° C. or greater and mostpreferably about 35° C. or greater.

The compositions may further comprise a variety of optional additives.One particularly useful additive is a thickener such as medium to high(about 10,000 to about 1,000,000) molecular weight polymethylmethacrylate which may be incorporated in an amount of about 10 to about60 weight percent, based on the total weight of the composition.Thickeners may be employed to increase the viscosity of the compositionto facilitate application of the composition.

Another particularly useful additive is an elastomeric material. Thematerials may improve the fracture toughness of compositions madetherewith which can be beneficial when, for example, bonding stiff, highyield strength materials such as metal substrates that do notmechanically absorb energy as easily as other materials, such asflexible polymeric substrates. Such additives can be incorporated in anamount of about 5 percent to about 35 percent by weight, based on thetotal weight of the composition. Useful elastomeric modifiers includechlorinated or chlorosulphonated polyethylenes such as HYPALON 30(commercially available from E. I. Dupont de Nemours & Co., Wilmington,Del.) and block copolymers of styrene and conjugated dienes(commercially available from Dexco Polymers under the Trademark VECTOR,and Firestone under the Trademark STEREON). Also useful, and even morepreferred, are certain graft copolymer resins such as particles thatcomprise rubber or rubber-like cores or networks that are surrounded byrelatively hard shells, these materials often being referred to as“core-shell” polymers. Most preferred are theacrylonitrile-butadiene-styrene graft copolymers available from Rohm andHaas. In addition to improving the fracture toughness of thecomposition, core-shell polymers can also impart enhanced spreading andflow properties to the uncured composition. These enhanced propertiesmay be manifested by a reduced tendency for the composition to leave anundesirable “string” upon dispensing from a syringe-type applicator, orsag or slump after having been applied to a vertical surface. Use ofmore than about 20 percent of a core-shell polymer additive is desirablefor achieving improved sag-slump resistance. Generally the amount oftoughening polymer used is that amount which gives the desired toughnessto the polymer or the adhesive prepared.

In a preferred embodiment the compositions of the invention contain aheat management material. Any material which functions to dissipate heatduring polymerization, may be used. Examples of useful heat managementmaterials include volatile liquids which evaporate during the reactionas a result of absorbing heat generated during the reaction, materialswhich function as heat sinks by absorbing generated heat and materialswhich react via an endothermic reaction under conditions of thereaction. Materials useful as heat sinks are materials with high heatcapacities. Examples of materials with high heat capacities includeceramic particles, glass beads, fluoropolymer powders, and hollowspheres. Useful liquid materials include, chlorinated alkanes, dialkylethers, alkanes, methylene chloride and low boiling petroleum ethers.More preferred solvents include methylene chloride, diethyl ether,pentane, hexane and the like. The amount of heat management materialused is dependent on the target reaction temperature and the heatcapacity of the heat management material. One skilled in the art canreadily determine the necessary amount of the heat management material.The heat of reaction can also be impacted by slowing down the rate ofmixing thereby allowing for slower heat generation. Preferably theaverage temperature of the adhesive over its' working time is managed toa target of about 70° C. or less, preferably about 60° C. or less andmost preferably about 50° C. or less. The heat management material canbe placed on either the resin side of the formulation or on the hardenerside. The selection of the heat management material and the amount ofthe heat management material are driven by the amount of heat that needsto be dissipated during the polymerization. If the heat generated duringthe reaction is too high for too long of a period of time, the adhesionof the polymerized composition to a substrate may be negativelyimpacted. It is desirable to limit the amount of heat induceddecomplexation of the organoborane amine complex. If the complexdecomplexes too rapidly adhesion is negatively impacted. In oneembodiment where heat management materials are used, the ratio of thenitrogen atoms to the boron atoms can be any workable ratio. Furtherwhere the heat management materials are used any of the knownorganoborane amine complexes and dissociation agents can be used.

Another useful adjuvant is a cross-linking agent. Cross-linking agentscan be used to enhance the solvent resistance of the adhesive bond orpolymer composition, although certain compositions of the invention havegood solvent resistance even in the absence of externally addedcross-linking agents. The crosslinking agent can increase the usetemperature and the solvent resistance of the cured polymer or adhesive.Typically employed in an amount of about 0.2 to about 10 weight percentbased on the total weight of the compositions, useful cross-linkersinclude the various diacrylates, referred to above as possible acrylicmodifying monomers, and compounds with both acrylate and isocyanatefunctionality as well as other materials. Particular examples ofsuitable cross-linking agents include ethylene glycol dimethacrylate,ethylene glycol diacrylate, triethyleneglycol dimethacrylate, diethyleneglycol bismethacryloxy carbonate, polyethylene glycol diacrylate,tetraethylene glycol dimethacrylate, diglycerol diacrylate, diethyleneglycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropanetris(2-methyl-1-aziridinepropionate, trimethylolpropane trimethacrylate,acrylate tipped polyurethane containing prepolymers, polyetherdiacrylates and dimethacrylates.

Peroxides may be optionally included (typically in an amount of about 2percent by weight or less, based on the total weight of thecomposition), for example, to adjust the speed at which the compositionspolymerize or to complete the polymerization.

Small amounts of inhibitors such as hindered phenols (i.e.2,6-di-tert-butyl-4-methylphenol, may be used, for example, to preventor reduce degradation of the olefinic monomers during storage.Inhibitors may be added in an amount that does not materially reduce therate of polymerization or the ultimate properties of an adhesive orother composition made therewith, typically about 10 to about 10,000 ppmbased on the weight of the polymerizable monomers.

The composition may also contain known catalyst for the reaction of anisocyanate reactive compound with an isocyanate containing compound.Such catalysts are well known in the art and are disclosed at Chaio U.S.Pat. No. 5,623,044 at column 6 line 1 to line 12, incorporated herein byreference.

The composition of the invention may contain a reactive or nonreactivediluent to balance the volume of the two parts of the composition so asto achieve a commercially acceptable volumetric ratio of the twocomponents. Preferably the diluent is a reactive diluent. Preferredreactive diluents are isocyanate reactive compounds because they reactwith the polyisocyanate to form a polyurea and/or a polyurethane phase.Representatives of this class of additive would be low equivalent weightalcohols, amines, aminols, polyamines, polyols or mixtures thereof.These reactive additives react with the isocyanate (decomplexing agent)and thus the amount of isocyanate must be increased to accommodate theseadditives. The polyurea/polyurethane phase can improve the properties ofthe final product. Generally this phase can increase the glasstransition temperature of the polymeric adhesive formed. The propertiesof the final cured composition can be adjusted by selection of thepolyisocyanate and the isocyanate reactive compound.

Other possible additives include non-reactive colorants, fillers,solvents etc. Solvents should be selected to have boiling points belowthe thermal dissociation temperature of the organoborane amine complex.The use of an excess of a nonreactive diluent can negatively impactcertain properties of the polymerized composition such as tensilestrength, thermal resistance and elongation.

The various optional additives are employed in an amount that does notsignificantly adversely affect the polymerization process or the desiredproperties of compositions made therewith.

Polymerizable compositions according to the invention may be used inwide variety of ways, including as sealants, coatings, primers, tomodify the surface of polymers, and injection molding resins. They mayalso be used as matrix resins in conjunction with glass and metal fibermats such as in resin transfer molding operations. They may further beused as encapsulants and potting compounds such as in the manufacture ofelectrical components, printed circuit boards and the like. Quitedesirably, they provide polymerizable adhesive compositions that canbond a diverse myriad of substrates, including polymers, wood, ceramics,concrete, glass and primed metals. Another desirable related applicationis their use in promoting adhesion of paints to low surface energysubstrates such as polyethylene, polypropylene,polyethyleneterephthalate and polytetrafluoroethylene, and theirco-polymers. In this embodiment the composition may be coated onto thesurface of the substrate to modify the surface to enhance the adhesionof the final coating to the surface of the substrate or added to thecoating itself.

The compositions of the invention can be used in coating applications.In such applications the composition may further comprise a carrier suchas a solvent. The coating may further contain additives well known tothose skilled in the art for use coatings such as pigments to color thecoating, inhibitors and UV stabilizers. The compositions may also beapplied as powder coatings and may contain the additives well known tothose skilled in the art for use in powder coatings.

The compositions of the invention can also be used to modify the surfaceof a polymeric molded part, extruded film or contoured object.Compositions of the invention can also be used to change thefunctionality of a polymer particle by surface grafting of polymerchains on to the unmodified plastic substrate.

Polymerizable compositions of the invention are especially useful foradhesively bonding low surface energy plastic or polymeric substratesthat historically have been very difficult to bond without usingcomplicated surface preparation techniques, priming, etc. By low surfaceenergy substrates is meant materials that have a surface energy of about45 mJ/m² or less, more preferably about 40 mJ/m² or less and mostpreferably about 35 mJ/m² or less. Included among such materials arepolyethylene, polypropylene, acrylonitrile-butadiene-styrene,polyamides, syndiotactic polystyrene, olefin containing blockco-polymers, and fluorinated polymers such as polytetrafluoroethlene(TEFLON) which has a surface energy of less than about 20 mJ/m². (Theexpression “surface energy” is often used synonymously with “criticalwetting tension” by others.) Other polymers of somewhat higher surfaceenergy that may be usefully bonded with the compositions of theinvention include polycarbonate, polymethylmethacrylate, andpolyvinylchloride.

The polymerizable compositions of the invention can be easily used as atwo-part adhesive. The components of the polymerizable compositions areblended as would normally be done when working with such materials. Thedecomplexing agent is usually included in this blend so as to separateit from the organoborane amine complex, thus providing one-part of thetwo-part composition. The organoborane amine complex of thepolymerization initiator system provides the second part of thecomposition and is added to the first part shortly before it is desiredto use the composition. The complex may be added to the first partdirectly or it may be pre-dissolved in an appropriate carrier such as areactive diluent or monomer, i.e., methyl methacrylate or a MMA/PMMAviscous solution or to a non-reactive diluent, such as a solvent, justprior to addition to the first part.

It may be desirable to store the complexes apart from the monomers,oligomers or polymers to inhibit premature polymerization of themonomers, oligomers or polymers. The complexes of this invention havegreatly enhanced stability when in the presence of monomers and in theabsence of a decomplexing agent, and thus can be stored with thepolymerizable components of the composition.

For a two-part adhesive such as those of the invention to be most easilyused in commercial and industrial environments, the volume ratio atwhich the two-parts are combined should be a convenient whole number.This facilitates application of the adhesive with conventional,commercially available dispensers. Such dispensers are shown in U.S.Pat. Nos. 4,538,920 and 5,082,147 (incorporated herein by reference) andare available from Conprotec, Inc. (Salem N.J.) under the trade nameMIXPAC. Typically, these dispensers use a pair of tubular receptaclesarranged side-by-side with each tube being intended to receive one ofthe two-parts of the adhesive. Two plungers, one for each tube, aresimultaneously advanced (e.g., manually or by a hand-actuated ratchetingmechanism) to evacuate the contents of the tubes into a common, hollow,elongated mixing chamber that may also contain a static mixer tofacilitate blending of the two-parts. The blended adhesive is extrudedfrom the mixing chamber onto a substrate. Once the tubes have beenemptied, they can be replaced with fresh tubes and the applicationprocess continued.

The ratio at which the two-parts of the adhesive are combined iscontrolled by the diameter of the tubes. (Each plunger is sized to bereceived within a tube of fixed diameter, and the plungers are advancedinto the tubes at the same speed.) A single dispenser is often intendedfor use with a variety of different two-part adhesives and the plungersare sized to deliver the two-parts of the adhesive at a convenient mixratio. Some common mix ratios are 1:1, 2:1, 4:1 and 10:1, but preferablyless than 10:1.

The part of the adhesive or polymerizable compositions of the inventionwhich contain the amineorganoborane complex preferably displays thermalstability at, or above, room temperature. Thermal stability as usedherein means the amine organoborane complex does not disassociate andinitiate polymerization of the olefinic unsaturated compounds present inthe composition. Thermal stability can be measured by determining thetemperature at which the viscosity of the composition begins toincrease. Preferably the temperature at which the viscosity of thecomposition increases is greater than about 40° C., more preferablygreater than about 60° C. and most preferably greater than about 80° C.The increase in viscosity indicates that the amine borane complex isdisassociating and polymerization has been initiated. In the embodimentwherein the composition is used as an adhesive, the adhesive preferablydemonstrates a lap shear strength of about 100 psi. (689 kPa) orgreater, more preferably about 250 psi (1724 kPa) or greater and morepreferably about 400 psi (2758 kPa) or greater according to thefollowing test procedure.

The adhesive components are mixed and applied to one or both substrates(1 in×4 in×⅛ in (25.4 mm×101.6 mm×3.2 mm) polypropylene coupons).Adhesive bead thickness may be controlled by the addition of a fewweight percent of glass beads between 0.005 to 0.030 inches in diameter(0.13 mm to 0.76 mm). The coupons are mated to provide 0.5 inch squared(161 mm²) to 1.0 inch squared (645 mm²) substrate overlap in a lap-sheartesting configuration. The samples are held in place with metal binderclips to provide constant force and facilitate the elimination of airbubbles in the adhesive during cure. The bonded samples were usuallycured for at least about 24 hours before being mounted in a tensiletesting apparatus (Instron) fitted with a sample oven. The samples areevaluated at crosshead speeds of 0.05 (0.13 mm) and 0.5 (12.7 mm) inchesper minute for room temperature and 110° C. testing conditions,respectively. Maximum load (pounds) to break are recorded and maximumstress (psi) is calculated by dividing this load by the overlap area(inches squared).

Preferably the mixed 2 part compositions of the invention have asuitable viscosity to allow application without dripping. Preferably,the viscosities of the two individual components should be of the sameorder of magnitude. Preferably the mixed compositions have the viscosityof about 100 (0.1 Pa.s) centipoise or greater, more preferably about1,000 (1.0 Pa.s) centipoise or greater and most preferably about 5,000(5.0 Pa.s) centipoise or greater. Preferably the adhesive compositionshave a viscosity of about 150,000 (150 Pa.s) centipoise or less, morepreferably about 100,000 (100 Pa.s) centipoise or less and mostpreferably about 50,000 (50 Pa.s) centipoise or less.

The additive package in a plastic substrate may impact the adhesion of acomposition of the invention to such substrate. Certain additives havebeen found to be incompatible with the active components of thecompositions of this invention. One skilled in the art can readilydetermine those additives which impact the adhesion by performing simpleadhesion studies on the substrate. Common additives which negativelyimpact adhesion are Irganox 1076, inhibitor available from CibaSpecialty Chemical Corporation and potassium iodide. Common additiveswhich do not significantly impact the adhesion include Irgaphos 168inhibitor, Tinuvin 328 inhibitor, Tinuvin 770 inhibitor, Irganox 1010inhibitor, available from Ciba Specialty Chemical Corporation, andCalcium stearate.

Specific Embodiments

The following examples are included for illustrative purposes only andare not intended to limit the scope of the claims. Unless otherwisestated all parts and percentages are by weight.

Preparation of Adhesive Compositions

Two component (part) adhesives are produced as described below. Onecomponent (hardener) includes the organoborane amine complex mixed with“reactive diluents” or “non-reactive diluents”. “Reactive diluent” meansa material or compound which is reactive with some component of theresin, either the acrylic (during polymerization), the initiator, orboth. Non-reactive diluents are not reactive with the resin components,such as glass spheres or low boiling solvents. Low boiling solvent isdefined as one which boils at a temperature below the disassociationtemperature of the organoborane amine complex, i.e., the temperature atwhich the complex decouples. The amount of diluent is established byviscosity control and/or volumetric concerns (to achieve a given volumeratio of hardener component to resin component). The other component(resin) is the acrylic resin with an initiator, for example, acrylicacid or more preferred an isocyanate, such as, isophorone diisocyanate,that decomplexes the organoborane amine complex, by reacting with theamine, when mixed with the hardener. The acrylic resin is a mixture ofmethylmethacrylate (MMA) and polymethylmethacrylate (PMMA, 350,000 amumol weight) except as noted hereinafter. The MMA and PMMA are stirred orrotated overnight to mix the PMMA into the MMA. The resin is 80/20weight percent MMA and PMMA, with an added amount of decomplexing agent(isocyanate), as shown by the percent IPDI (Isophorone diisocyanate,unless otherwise stated) column. The resulting acrylic resin plusinitiator preferably has a viscosity of about 1000 to 50,000 centipoise(cP) (1.0 Pa.S to 50 Pa.S). The above procedure provides the preferredmode of formulation, where no polymerizable species is added to thehardener side of the 2 part adhesive. This formulation gives very longshelf life (>5 weeks at 50° C.).

The adhesive may be mixed in the desired ratio in air, in a bag, orthrough a pressurized gun. The adhesive is applied to test strips 1 inch(25.4 mm) wide with a ½ inch (12.7 mm) overlap and is tested foradhesive strength as described previously. Polypropylene is used for lowtemperature tests and syndiotactic polystyrene (SPS)/nylon blends ore-coated metal sheets are used for high temperature testing. Hightemperature testing is performed on an Instron test machine as describedabove. The test strip is equilibrated to the desired temperature in theInstron tester's oven for at least 5 minutes before the test is started.

Polymerizable compositions of the invention containing amineorganoborane complexes were prepared and tested as described herein.

The following abbreviations are used in the Tables.

Am refers generally to amines as specified which are complexed with theborane.

PBMA is polybutylmethacrylate.

H is Hardener.

R is Resin.

MOPA is methoxy propylamine.

MeCl2 is methylene chloride.

Dytek A is 2-methyl-1,5-diaminopentane, sold by Dupont Co.

HMDI is hexamethylene diisocyanate.

TDI is 2,4-toluene diisocyanate.

P-94 is PAPI*-94 polymeric MDI, with 2.4 average equivalents NCO/mol.

P-27 is PAPI*-27 Polymeric MDI, with 2.7 average equivalents NCO/mol.

UnRd is an unreactive diluent.

DMAPA is dimethylaminopropylamine.

TBB is tri-n-butyl borane.

PMMA is polymethyl methacrylate.

IPDA is cis or trans isophorone diamine.

VS5500 refers to a hollow glass sphere product of the 3M Corporation.

Cabosil is a trademark of The Cabot Corporation for colloidal silicaparticles.

AP Si is aminopropyl silanized silica gel.

N2PPO 300 (or N2-300) isO-(2-aminopropyl-O′-(2-methoxyethyl)polypropylene glycol) (300 Eq. Wt.).IPDI is isophorone diisocyanate.

Polycap 300 is 300 molecular weight polycaprolactone triol.

N2PPO 115 is 115 amu (atomic mass unit) equivalent weight poly(propyleneglycol)bis(2-amino-propyl ether).

N2PPO 450 is 450 amu equivalent weight poly(propyleneglycol)bis(2-amino-propyl ether).

N2PPO 1000 is 1000 amu equivalent weight poly(propyleneglycol)bis(2-aminopropyl ether).

DEA is diethanol amine.

E400 is an ethylene oxide based diol having a molecular weight of about400.

T-9 is stannous octanoate tin catalyst for urethane polymerizationavailable from Air Products Corporation.

N2-C9 is diamino nonane.

RD is reactive diluent.

*PAPI is a Trademark of The Dow Chemical Company.

In Examples 1 to 71 the hardener was prepared by mixing the reactivediluent (RD), the amine (Am) plus organoborane (TBB) as the organoboraneamine complex and VS5500 glass spheres in the weight ratios as describedbelow, generally a total of 5 grams of these components were used. InExamples 72-91 the hardener was made by mixing the organoborane aminecomplex, the reactive diluent, unreactive diluent, amine and VS5500 inthe weights specified below. In Examples 87 to 91 the hardener wasprepared by mixing the VS5500 glass spheres, organoborane (TBB),unreactive diluent (UnRD), reactive diluent (RD) and the amine (Am) inthe weights specified below. All of the formulations used in theseexamples had a 4:1 resin:hardener mix ratio, by volume, except Examples72 to 86 wherein the hardener to resin mix ratios were as specified inTable 3 and C-2 which was 25:1. The adhesive was applied topolypropylene substrates or e-coated metal, or other high temperaturesubstrate, as described hereinabove. Also tabulated are values for theamount of organoborane in the hardener as a weight percent (% TBB/H),the amine nitrogen atom to boron atom ratio (N/B ratio), the aminenitrogen plus any other active hydrogen equivalents to isocyanatereactive group ratio (N/NCO ratio), the weight percent urea as definedby the weight of all the amine plus isocyanate normalized by the totalweight of the adhesive. Lap shears were determined on a tensile testingapparatus as described above. In the tables referring to lap shearresults>means substrate failure occurs prior to adhesive failure.

EXAMPLES 1 TO 53

In Examples 1 to 53 all hardeners were formulated to make 5.0 grams. InExamples 1 to 4, 20 percent by weight of a polymer diluent of apolymethylmethacrylate polybutylmethacrylate copolymer having a 75,000amu molecular weight was blended into the reactive diluent. In all ofExamples 1 to 19 and 22-53, the TBB/H percent ratio was 10 (10 percentof the hardener by weight is TBB). In Examples 20 and 21 theorganoborane used was triethylborane. The amount of triethylboranepresent was 0.27 g and the TEB/H percent ratio was 5.4. In Examples 37and 41 the isocyanate was HMDI. In Example 38 the isocyanate was toluenediisocyanate. In Examples 39 and 42 the isocyanate was a polymeric MDIavailable from The Dow Chemical Company under the trademark anddesignation PAPI 94. In Examples 40 and 43 the isocyanate used was apolymeric MDI available from The Dow Chemical Company under thetrademark and designation PAPI 27. In Examples 44-47 the reactivediluent is given as a weight ratio of the components listed by thevalues in the parentheses. In Examples 48, 49, and 51 the amine used asa reactive diluent is a solid, amine capped polypropylene oxide (1000mw) dissolved in a liquid amine at a 1:1 weight ratio. In Example 50 thevolume amounts of solid N2-PPO to liquid Dytek A in the reactive diluentwas 75 percent to 25 percent, respectively. In Examples 52 and 53 thereactive diluents are a mixture of the listed amine and diamino nonaneat a 1:1 weight ratio. In the examples where the amount of VS5500 in thereactive diluent is not specifically given as a ratio (Examples 25, 29,49, and 51), the amount of glass is 40% by weight of the total weight ofthe hardener. The density of the resin in Table 1 is 1.

Table 1 illustrates the effectiveness of different classes of amines andamine blends with alcohols and nonreactive diluents. Also shown in Table1 are examples using various isocyanates as the decomplexing agent. Thegeneral classes shown here are: polymer thickened amines, higherfunctional amines and aminols, oligomeric diamines, blends of solid andliquid amines, and blends of amines and alcohols and diols. Among theamines are structural variants including mono-amines, diamines, brancheddiamines, aliphatic cyclic amines, alkanolamines, diamines with primaryand higher order amines, and polyether amines. The results in Table 1demonstrate that excellent adhesion to plastic substrates is achieved bythe compositions described.

TABLE 1 125 C Exam- RD Am Density % RT Lap Rt Lap 125 C Lap ple ReactiveDiluent (RD) Wt. Am Wt. N/B % IPDI H N/NCO Urea (psi) (kPa) (e-coat)(kPa) 1 DMAPA 3.85 IPDA 0.65 13.8 25 0.9 0.76 34.1 168 (1158) 2 MOPA3.85 IPDA 0.65 15.4 25 0.92 0.86 34.3 226 (1558) 3 IPDA 3.85 IPDA 0.6516.0 25 0.98 0.95 34.8 >390 (>2689) 4 Hexylamine 3.85 IPDA 0.65 13.9 250.85 0.72 33.7 224 (1544) 5 IPDA 3.85 IPDA 0.65 19.2 30 0.92 0.90 41.2333 (2296) 6 75/25 IPDA/VS5500 3.85 IPDA 0.65 15.1 25 0.74 0.6832.1 >581 (>4005) 7 75/25 IPDA/VS5500 3.85 IPDA 0.65 15.1 20 0.74 0.8527.9 249 (1717) 8 75/25 IPDA/VS5500 + Cabosil 3.85 IPDA 0.65 15.1 250.74 0.68 32.1 276 (1902) (.17 g) 9 IPDA/AP Si (6.7/33) 3.85 IPDA 0.6513.8 25 1.12 0.94 33.5 127 (876) 10 MOPA/MeCl2 50/50 3.85 IPDA 0.65 10.720 0.98 0.80 33.8 >488 (>3364) 11 75/25 MOPA/VSS500 3.85 IPDA 0.65 14.625 0.71 0.63 31.9 322 (2220) 12 MOPA/Cabosil (0.75 g) 4.16 MOPA 0.3415.1 25 0.95 0.87 34.6 122 (841) 13 75/25 MOPA/AP Si-VS5500 3.85 IPDA0.65 14.6 25 0.71 0.63 31.9 338 (2330) 14 Morpholine/AP Si (67/33) 3.85IPDA 0.65 13.5 25 1.04 0.86 33.0 248 (1710) 15 DMAPA 3.85 IPDA 0.65 16.530 0.84 0.70 40.4 156 (1076) 16 Hexylamine 3.85 IPDA 0.65 16.6 30 0.80.68 40.0 164 (1131) 17 Dytek A/MeCl2 (51:50) 3.85 IPDA 0.65 14.9 250.96 0.87 37.6 >622 (>4289) 18 Dytek A/MeCl2/VS5500 4.05 Dytek 0.45 9.215 0.53 0.49 23.8 220 (1517) (25/25/50) A 19 (50/50) Dytek A/VS 55004.16 MOPA 0.34 14.4 25 0.58 0.51 28.0 250 (1724) 20 (55/45) Dytek A/VS5500 4.41 Dytek 0.32 31.9 25 0.58 0.61 28.2 >302 (>2082) A 21 (55/45)Dytek A/VS 5500 4.41 Dytek 0.32 31.9 15 0.58 1.02 19.5 >637 (>4392) A 22N2PPO 300 3.85 IPDA 0.65 7.5 15 1.02 0.77 30.2 293 (2020) 23 N2PPO 3002.19 N2-300 2.31 5.5 10 1 0.83 26.0 >473 (>3261) >665 (>4585) 24 N2PPO300/VS5500 (50/50) 2.19 N2-300 2.31 4.1 5 0.75 0.95 18.4 >595(>4102) >223 (>1538) 25 IPDA/MOPA (50/50)/S5500 3.85 IPDA 0.65 10.8 150.6 0.66 24.8 >428 (>2951) 26 N2PPO 300/MOPA (50/50) 3.85 IPDA 0.65 13.020 0.95 0.94 33.4 418 (2882) 27 Polycap 300/MOPA (50/50) 4.16 MOPA 0.3417.5 30 0.95 0.84 41.5 170 (1172) 28 Polycap 300/IPDA (75/25) 3.85 IPDA0.65 17.4 30 1 1.03 42.0 166 (1145) 29 N2PPO 300/IPDA 3.85 IPDA 0.65 8.110 0.6 0.74 20.4 >617 (>4254) (50/50)/VS5500 30 N2-Menthane 3.85 IPDA0.65 19.3 30 0.92 0.90 41.2 318 (2193) 31 N2PPO 115 3.85 IPDA 0.65 15.025 0.95 0.87 37.5 295 (2034) 32 N2PPO 450 3.85 IPDA 0.65 5.9 10 1.040.94 26.5 190 (1310) 33 Diethanol amine (DEA) 3.85 IPDA 0.65 16.1 501.06 1.38 58.4 255 (1758) 34 75/25 DEA/VS5500 3.85 IPDA 0.65 32.8 40 0.81.00 45.1 240 (1655) 35 Methyl benzyl amine (MBA) 3.85 IPDA 0.65 14.4 250.95 0.83 37.5 164 (1131) 36 Ethanolamine/VS5500 50/50 3.85 IPDA 0.6514.3 25 0.6 0.94 33.5 >603 (>4158) 37 60/40 IPDA/75K PMMA 3.85 IPDA 0.6512.7 HMDI, 1.05 1.03 24.2 240 (1655) 15 38 60/40 IPDA/75K PMMA 3.85 IPDA0.65 12.7 TDI, 20 1.05 0.80 28.2 304 (2096) 39 50/50 IPDA/VS5500 3.85IPDA 0.65 11.0 P-94, 0.6 0.84 29.5 >416 (>2868) 15 40 60/40 IPDA/75KPMMA 3.85 IPDA 0.65 12.7 P27, 25 1.07 0.87 32.2 163 (1124) 41 80/20IPDA/75K PMMA 3.85 IPDA 0.65 16.0 HMDI, 0.98 0.91 30.7 321 (2213) 20 4280/20 MOPA/75K PMMA 4.16 MOPA 0.34 15.0 P-94, 0.89 0.85 37.9 190 (1310)30 43 80/20 MOPA/75K PMMA 4.16 MOPA 0.34 15.0 P27, 25 0.89 0.85 33.8 169(1165) 44 Gly/IPDA/PMMA (1/4.2/25) 3.85 IPDA 0.65 17.2 11.6 1.05 0.7 38102 (703) 45 DEA/IPDA/VS550 (1/1/2) 3.85 IPDA 0.65 14.5 10.2 0.6 1.0430 >668 (>4606) 46 Gly/MOPA/PMMA 4.16 MOPA 0.34 16.5 12.7 1.05 0.65 38169 (1165) (1/4.2/2.8) 47 DEA/MOPA/PMMA 4.16 MOPA 0.34 16.1 12.6 1.050.77 38 171 (1179) (1/38/2.5) 48 N2-PPO (1000)/DMAPA 3.85 IPDA 0.65 10.415 0.94 0.94 29.3 94 (648) 49 N2-PPO/DMAPA/VS5500 3.85 IPDA 0.65 6.6 100.6 0.60 20.4 >584 (>4027) 50 N2-PPO 1000/Dytek A 3.85 IPDA 0.65 9.9 151.01 1.01 30.1 211 (1455) 51 N2-PPO (1000)/Dytek 3.85 IPDA 0.65 9.2 100.6 0.84 20.4 >478 (>3296) A/VS5500 52 N2-C9/DMAPA 3.85 IPDA 0.65 18.530 0.87 0.82 40.7 221 (1524) 53 N2-C9/IPDA 3.85 IPDA 0.65 19.9 30 0.910.92 41.1 248 (1710)

EXAMPLES 54 TO 71

Examples 54 to 73 were performed with varying amounts of organoboraneTBB (tributyl borane) catalyst in the formulation of the hardener, andvarying N/B ratios. In these Examples the organoborane amine molar ratiois 1:0.5 molar for the triethylborane Dytek A amine complex and 1:1.4for the other complexes. In all of Examples 54 to 77 and C1, thereactive diluent included 40 percent by weight of VS5500. Theorganoborane used in Examples 57, 62 and 68-71 was triethylborane (TEB).

TABLE 2 TBB Reactive RD Amine Am % RT Lap RT Lap 125 C 125 C Lap Examplewt Diluent (RD) wt. (Am) wt TBB/H N/B % IPDI N/NCO % Urea (psi) (kPa)(psi), e-coat (kPa) 54 0.26 IPDA 4.40 IPDA 0.34 1.0 22.5 14 0.77 22.2209 (1441) 800 (5516) 55 0.52 IPDA 3.80 IPDA 0.68 2.1 10.2 12.5 0.7820.6 39 (269) 650 (4482) 56 0.778 IPDA 3.20 IPDA 1.02 3.1 6.1 11 0.7918.9 >613 (>4226) 1900 (13100) 57 0.42 IPDA 3.56 IPDA 1.02 1.7 13.1 130.78 21.4 >654 (>4509) 1350 (9308) 58 1.035 IPDA 2.61 IPDA 1.36 4.1 4.110 0.77 17.7 388 (2675) 1400 (9653) 59 0.26 MOPA 4.56 MOPA 0.18 1.0 21.513 0.79 21.3 284 (1958) 400 (2758) 60 0.52 MOPA 4.12 MOPA 0.36 2.1 9.711.5 0.81 19.5 >488 (>3664) 350 (2413) 61 0.778 MOPA 3.69 MOPA 0.53 3.15.8 10.5 0.79 18.2 >810 (>5584) 1000 (6894) 62 0.42 MOPA 4.05 MOPA 0.531.7 12.6 12 0.80 20.3 >886 (>6108) 630 (4344) 63 1.035 MOPA 3.26 MOPA0.71 4.1 3.9 9 0.82 16.5 >531 (>3661) 250 (3103) 64 0.26 Dytek A 4.51Dytek A 0.23 1.0 33.0 20 0.79 27.4 202 (1393) 450 (3103) 65 0.52 Dytek A4.02 Dytek A 0.46 2.1 15.0 17.5 0.81 24.8 234 (1613) 600 (4136) 66 0.778Dytek A 3.53 Dytek A 0.69 3.1 9.0 16 0.80 23.1 391 (2696) 600 (4137) 671.035 Dytek A 3.04 Dytek A 0.92 4.1 6.0 14 0.81 20.9 350 (2413) 440(3034) 68 0.14 Dytek A 4.78 Dytek A 0.08 0.6 34.5 20 0.82 27.6 31 (214)550 (3792) 69 0.28 Dytek A 4.55 Dytek A 0.17 1.1 30.5 19.5 0.80 26.9 303(2089) 400 (2758) 70 0.418 Dytek A 4.33 Dytek A 0.25 1.7 19.4 18.5 0.8025.8 >551 (>3799) 575 (>3964) 71 0.558 Dytek A 4.11 Dytek A 0.33 2.213.7 17.5 0.80 24.7 >543 (>3744) 650 (4482) C-1¹ 0.778 IPDA 3.20 IPDA1.02 4.69 6.1 7²  .80 0 Soft — 30 (207) C-2² 0.88 0 0 MOPA 0.59 3.851.36 4² — 0 >578 (>3985) 280 (1930 Examples ¹Comparative Example²Acrylic Acid Decomplexing Agent.

All adhesives of the invention gave good strength at room and hightemperature. A comparative example (C-1) with the high N/B ratio of thepresent invention but using AA (acrylic acid) instead of isocyanate asthe initiator produced a poor adhesive at all temperatures. A secondcomparative example (C-2), using a low N/B ratio, a 25:1 mix ratio, andacrylic acid initiation, produced a good room temperature adhesive, buta poor adhesive at elevated temperature compared to the subject of thepresent invention. In the second comparative example the complex wasmade by adding 1.36 moles of MOPA to 1 mole of TBB. 4 weight percent ofthat complex was added to a resin consisting of 80 parts MMA and 20parts PMMA (350 k Mw) with 4 weight percent acrylic acid added. Themixture was applied to polypropylene or e-coated metal substrates fortesting at RT or 125° C., respectively. The adhesive was allowed to cureover 3 days before testing.

EXAMPLES 72-86

Several adhesive formulations were prepared as described above. InExamples 72 to 77 the reactive diluent and amine were both isophoronediamine. In Examples 78 to 82 the reactive diluent and amine were bothMOPA and the unreactive diluent was methylene chloride. In Examples 83to 86 the amine and reactive diluent were Dytek A. Lap shear testing wasperformed on plaques made of a blend of nylon-6 and syndiotacticpolystyrene (SPS) at 125 and 150° C. For the lap shear tests in Examples72 to 77 at 150° C., and 78 to 82 at 125° C., the plaques contained 30percent SPS in nylon 6. Examples 72 to 77 and 83-86 tested at 125° C.used plaques containing 15 percent of SPS in nylon 6.

Examples 72 to 86 illustrate for different amine based hardeners, andthe effect of a changing N/B ratio on high temperature lap shears.Constant in the each set of series is the amount of organoborane in theadhesive (not constant in the hardener), amount of filler (VS5500)/gliquid in the hardener, and the N/NCO ratio. Unique in these examplesare the mix ratio (R/H, Resin/Hardener), which varied in 2 of theseries. The resin was as described previously. FIG. 1 shows theincreasing lap shear strength as a function of increasing the N/B ratio.Low N/B ratio adhesives also have good strength due to the use ofsolvent and/or VS5500 glass spheres as heat management aids.

TABLE 3 TBB VS5500 UnRD RD Am % TBB % 125 C Lap 150 C Lap Example wt Wt.wt % wt. wt. in H R/H³ N/B % IPDI N/NCO Urea Psi (kPa) Psi (kPa) 72 1.087.41 9.48 0.55 5.82 5.40 19.89 15.00 0.87 21.12 546 (3765) 73 1.04 5.566.76 0.53 7.46 7.20 15.06 11.00 0.87 16.07 1190 (8204)  74 1.00 3.774.15 0.51 10.56 10.60 10.02 7.00 0.87 10.66 1084 (7474)  483 (3330) 750.96 2.13 1.74 0.49 18.02 18.80 4.98 3.30 0.88 5.25 966 (6660) 76 0.941.36 0.61 0.48 27.76 29.50 2.48 1.60 0.89 2.60 350 (2413) 77 0.93 0.930.00 0.48 40.04 43.00 1.07 0.70 0.86 1.14 817 (5633) 381 (2627) 78 1.1410.00 2.00 11.25 0.61 4.55 4.00 21.33 17.50 0.85 23.49 338 (2330) 791.14 10.00 5.00 8.25 0.61 4.55 4.00 15.93 13.00 0.85 17.49 267 (1841) 801.14 10.00 8.00 5.25 0.61 4.55 4.00 10.54 8.60 0.85 11.57 248 (1710) 811.14 10.00 11.00 2.25 0.61 4.55 4.00 5.15 4.20 0.85 5.65 233 (1606) 821.14 10.00 13.25 0.00 0.61 4.55 4.00 1.10 0.90 0.85 1.21 172 (1186) 832.06 5.71 5.79 0.72 14.40 7.00 9.93 14.50 0.86 18.39 882 (6081) 84 1.953.39 2.45 0.68 23.04 11.80 5.03 7.00 0.86 9.34 843 (5812) 85 1.90 2.290.86 0.67 33.30 17.50 2.51 3.40 0.86 4.66 745 (5137) 86 1.88 1.70 0.000.66 44.10 23.50 1.13 1.50 0.86 2.09 712 (4909) ³Volume ratio.

EXAMPLES 87-91

Adhesive formulations were prepared using the MMA-PMMA resin side asdescribed before and a hardener side as described in Table 4, whereinthe unreactive diluent is methyl methacrylate, the reactive diluent isisophorone diamine, the hardener side contains 6.0 grams of a VS5500glass bead formulation (Example 91 uses 4.5 grams in the hardener and1.5 grams in resin of VS5500), the amine weight is 1.2 g, the resin tohardener volume ratio is 4.0:1.0 and the amine equivalent to isocyanateequivalent ratio is 0.8. FIG. 2 shows the cure rate of the series ofadhesives at varied N/B ratios. The lines are cubic fits to the timedata so as to observe graphically the time at which the adhesives cureto a given strength, 50 psi (Green Time). For these adhesives the Greentimes are 39, 38, 25.6, 26.3, 27.7 minutes for N/B ratios of 1.1, 3, 4,6.1, 9.9, respectively. The Green time for even low N/B ratios is gooddue to the selection of decomplexer, acrylic resin components, and heatmanagement components.

TABLE 4 Green TBB UnRD RD % TBB % % Time Example wt wt. wt. in H N/BIPDI Urea (min) 87 2.3 5.5 0.0 15.6 1.1 2.0 2.8 39 88 2.3 3.4 2.1 15.63.0 5.4 7.6 38 89 2.3 2.3 3.2 15.6 4.0 7.3 10.2 25.6 90 2.3 0.0 5.5 15.66.1 11.0 15.4 26.3 91 2.4 0.0 9.9 13.3 9.9 18.0 24.7 27.7

What is claimed is:
 1. A two part composition useful for initiating cureof one or more polymerizable monomers which cure when exposed to freeradicals, the composition comprising in one part an organoboraneaminecomplex and in a second part an isocyanate which is capable ofdecomplexing the organoborane complex wherein the equivalent ratio ofamine nitrogen atoms to boron atoms is greater than 4.0:1 wherein theequivalents ratio of isocyanate to amine is greater than 1:0:1.0.
 2. Thetwo part composition according to claim 1 wherein the equivalent ratioof amine to isocyanate is 1.25:1.0 or less.
 3. The two part compositionaccording to claim 2 wherein the amine to isocyanate equivalent ratio isless than 1.0:1.0.
 4. The two part composition according to claim 3wherein the organoborane comprises a trialkyl borane or an alkylcycloalkyl borane and the amine comprises a primary amine; a secondaryamine; a polyamine having primary or secondary amines or both; ammonia;polyoxyalkylene amines; the reaction product of a diamine and adifunctional compound having moieties which react with an amine, whereinthe reaction product has terminal amine groups; aryl amities;heterocyclic amines; a compound having an amidine structural component;aliphatic heterocycles having at least one secondary nitrogen in theheterocyclic ring wherein the heterocyclic compound may also contain oneor more additional secondary or tertiary nitrogen atoms, oxygen atoms,sulfur atoms, or double bonds in the heterocycle; alicyclic compoundshaving bound to the alicyclic ring one or more substituents containingan amine moiety; conjugated imines or a mixture thereof.
 5. Acomposition according to claim 4 wherein the complex of the organoboraneand the amine corresponds to the formula

the organoborane heterocyclic amine complex corresponds to the formula;

the organoborane amidine complex corresponds to the formula

the organoborane conjugated imine complex corresponds to the formula

the organoborane alicyclic compound with an amine containing substituent

corresponds to the formula wherein B is boron; R¹ is separately in eachoccurrence hydrogen, a C₁₋₁₀ alkyl or C₃₋₁₀ cycloalkyl; R² Is separatelyin each occurrence a C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl or two or more of R²may combine to form a cycloaliphatic ring structure; R³ is separately ineach occurrence hydrogen, a C₁₋₁₀ alkyl or C₃₋₁₀ cycloalkyl; R⁴ isseparately in each occurrence hydrogen, C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl,C₆₋₁₀ aryl or C₆₋₁₀ alkaryl; R⁵ is separately in each occurrencehydrogen, C₁₋₁₀ alkyl, or C₃₋₁₀ cycloalkyl; R⁶ is separately in eachoccurrence hydrogen, a C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl or —N(R⁵)₂; R⁷ isseparately in each occurrence hydrogen, C₁₋₁₀ alkyl or C₃₋₁₀ cycloalkyl;two or more of R⁵, R⁶ and R⁷, in any combination, can combine to form aring structure which can be a single ring or a multiple ring structureand the ring structure can Include one or more of nitrogen, oxygen orunsaturation in the ring structure; R⁹ is independently in eachoccurrence hydrogen, C₁₋₁₀ alkyl or C₃₋₁₀ cycloalkyl, Y,—(C(R⁹)₂—(CR⁹═CR⁹)_(c)—Y or two or more of R⁹ can combine to form a ringstructure, or one or more of R⁹ can form a ring structure with Yprovided the electron rich group in Y is conjugated with respect to thedouble bond of the imine nitrogen; X is a hydrogen-bond acceptinggroup,; Y is independently in each occurrence hydrogen, —N(R⁴)₂, —OR⁴,—C(O)OR⁴, a halogen or an alkylene group which forms a cyclic ring withit R⁹; Z is separately in each occurrence oxygen or —NR⁴; a isseparately in each occurrence an integer of from about 1 to about 10; bis separately in each occurrence 0 or 1, with the proviso that the sumof a and b should be from about 2 to about 10; c is separately in eachoccurrence an integer of from about 1 to about 10; x is separately ineach occurrence an integer of about 1 to about 10, with the proviso thatthe total of all occurrence of x is from about 2 to about 10; and y isseparately in each occurrence about 0 or
 1. 6. A two part polymerizablecomposition comprising part 1, a) an organoboraneamine complex whereinthe ratio of amine nitrogen atoms to boron atoms is greater than 0:1;and part 2, b) one or more of monomers, oligomers or polymers havingolefinic unsaturation which is capable of polymerization by free radicalpolymerization, and c) an effective amount of an isocyanate which causesthe complex to disassociate, treeing the borane to initiatepolymerization of the one or more monomers, oligomers or polymers havingolefinic unsaturation; wherein the compound which causes disassociationof the complex is kept separate from the complex until initiation ofpolymerization is desired.
 7. A two part polymerizable compositionaccording to claim 6 wherein the ratio of amine to boron atoms is about5.0:1 or greater.
 8. A two part polymerizable composition according toclaim 7 wherein the equivalent ratio of amine to isocyanate is 1.25:1.0or less.
 9. A two part polymerizable composition according to claim 8wherein the amine to isocyanate equivalent ratio is less than about1.0:1.0.
 10. A two part polymerizable composition according to claim 9wherein the organoborane comprises a trialkyl borane or an alkylcycloalkyl borane and the amine comprises a primary amine; a secondaryamine; a polyamine having primary and/or secondary amines; ammonia;polyoxyalkylene amines; the reaction product of a diamine and adifunctional compound having moieties which react with an amine whereinthe reaction product has terminal amine groups; aryl amines;heterocyclic amines; a compound with an amidine structural component;aliphatic heterocycles having at least one secondary nitrogen in theheterocyclic ring wherein the heterocyclic compound may also contain oneor more additional secondary or tertiary nitrogen atoms, oxygen atoms,sulfur atoms, or double bonds in the heterocycle; alicyclic compoundshaving bound to the alicyclic ring one or more substituents containingan amine moiety; conjugated imines and mixtures thereof.
 11. A two-partcomposition according to claim 6 wherein the equivalents ratio ofisocyanate to amine is greater than 1.0:1.0.
 12. A method ofpolymerization comprising contacting the components of the polymerizablecomposition of claim 11 under conditions such that the one or moremonomers, oligomers, or polymers undergo polymerization.
 13. The methodof claim 12 wherein the contacting occurs at, or near, ambienttemperature.
 14. The method claim 13 which further comprises the step ofheating the composition to an elevated temperature under conditions suchthat the amine and isocyanate may react further.
 15. A method of bondingtwo or more substrates together which comprises a. contacting thecomponents of the composition of claim 11 together under conditions suchthat polymerization is initiated; b. contacting the adhesive compositionwith the two or more substrates; c. positioning the two or moresubstrates such that the adhesive composition is located between the twoor more substrates wherein they are in contact with one another; and c.allowing the adhesive to cure so as to bind the two or more substratestogether.
 16. A method of bonding two or more substrates according toclaim 15 which further comprises heating the adhesive composition to atemperature such that the amine and isocyanate react further.
 17. Themethod of claim 16 wherein the adhesive composition is heated to atemperature at or above the expected maximum use temperature of theadhesive.
 18. A method of modifying the surface of a low surface energypolymer by contacting a composition according to claim 11 with at leasta portion of the surface of the low surface energy polymer and causingthe complex to disassociate thereby initiating polymerization of themonomer, oligomers, polymers or mixture thereof such that the polymerformed is on the surface of the low surface energy polymer.
 19. A methodat coating a substrate which comprises contacting the components of thecomposition of claim 11; contacting the contacted composition with oneor more surfaces of a substrate; and allowing the coating Composition tocure.
 20. A coating composition which comprises the composition of claim11.
 21. A laminate comprising at least two substrates having disposedbetween the substrates and bound to each substrate a compositionaccording to claim 11.